The aim of this work, is realize heparin array by exploiting photolithografic process and micro-contact-printing in order to capture red blood cells infected by Plasmodium Falciparum (pRBCs), the malaria parasite, onto anti-fouling/fouling release UV-curable perfluoropolyether (PFPE-DMA) substrate. Two PFPE-DMAs materials were evaluated and their performance compared. Finally, it was decided to use a blend composed of two different molecular weight PFPE-DMAs in equal parts. Heparin was chosen because of its role as competitors towards pRBCs, which during the blood phase bind healthy red blood cells, with serious consequences including death. Heparin arrays are highly selective thus allowing an orderly arrangement of target cells on the substrate. Two different strategies were employed for heparin patterning: (i) biotinylated-heparin was linked to avidin patterned on an underlying photobiotin array, chemically linked to the substrate and obtained by μ-contact printing, exploiting the high affinity between biotin and avidin; (ii) methacrylated-heparin was directly bound to the unreacted double bonds of a partially cross-linked PFPE surface through a photo-lithographic process. The first method is characterized by high versatility, indeed any biotinylated molecule may bind the avidin array, and this method offers the possibility of isolating different rare cells. The photolithographic method allows the pattern realization in a single step, because it provides a direct grafting of the biomolecule onto the substrate.
The patterned surfaces could be integrated in microfluidic devices. These devices were produced by two methods, photolithography and replica molding. Also microstructured PFPE-DMA surfaces were created, and the microstructure ends were functionalized by micro-contact printing with heparin pattern. Microfluidic devices with integrated surface functionalized with biomolecular baits allow more selective immobilization of target cells under dynamic conditions, thus better exploiting the antifouling and fouling-release PFPE-DMAs properties. Furthermore, the use of microstructured microchannels allows a better interaction biomolecule bait-target cell.